Historic shake-up at the top of the ADF as Australia confronts a more uncertain world
Australia’s defence leadership is undergoing a significant and historic transition, with a new generation of military chiefs stepping into command at a time of rising global instability and strategic pressure.
In an announcement from Canberra, the Prime Minister confirmed sweeping changes across the Australian Defence Force (ADF), including the appointment of Vice Admiral Mark Hammond as the next Chief of the Defence Force (CDF), alongside new chiefs of Navy and Army.
A new Chief of the Defence Force
Vice Admiral Hammond’s elevation marks a symbolic and operational shift.
A submariner by trade and current Chief of Navy, Hammond becomes the first CDF to have begun his career as an enlisted sailor — a journey described by the Defence Minister as going “from scrubbing decks” to leading the entire force.
His appointment comes at a critical moment, with Australia deep in the implementation phase of the 2024 National Defence Strategy and the AUKUS submarine program reshaping long-term capability.
Hammond himself struck a measured tone, describing the role as “the most humbling moment” of his career and signalling continuity, with an initial focus on a smooth handover and maintaining operational readiness.
A historic first for the Australian Army
Perhaps the most notable milestone is the appointment of Lieutenant General Susan Coyle as Chief of Army — the first woman in Australian history to lead a service.
Her career spans from enlisting in the Army Reserve in 1987 through to commanding major operational and strategic roles, including deployments in Afghanistan and leadership of joint task forces.
The Defence Minister framed the appointment as more than symbolic, noting its impact on future generations: “You cannot be what you cannot see.”
Navy leadership aligned with AUKUS future
Rear Admiral Matthew Buckley will step up as Chief of Navy, bringing deep experience in submarine operations and nuclear capability development.
His background — including command of HMAS Collins and early leadership within Australia’s nuclear submarine program — positions him squarely at the centre of the Navy’s most consequential transformation in decades.
Together, Hammond and Buckley represent a leadership cohort heavily shaped by the strategic pivot toward undersea and long-range capabilities.
Honouring long-serving leaders
The changes also mark the departure of two of the ADF’s most experienced leaders.
Outgoing CDF Admiral David Johnson leaves after a remarkable 48-year career, while Chief of Army Lieutenant General Simon Stewart is credited with driving major structural reforms following the Defence Strategic Review.
Both were acknowledged for steering the force through a period of rapid change and increased strategic demand.
Leadership change amid global uncertainty
The reshuffle comes against a backdrop of escalating global tensions and economic disruption, particularly around energy security.
In the same press conference, the Prime Minister pointed to volatility in fuel markets and instability in the Middle East as evidence that Australia is operating in “very uncertain times” — reinforcing the need for strong, coordinated leadership across defence and government.
Questions around fuel reserves, supply chains, and Australia’s strategic preparedness underscored the broader context in which the new defence leadership will operate.
Inside Canberra analysis
This is more than a routine leadership rotation.
Three themes stand out:
- Operational continuity with strategic acceleration — leadership drawn from those already implementing AUKUS and the National Defence Strategy
- Cultural shift in leadership pathways — both Hammond and Coyle rose from enlisted ranks, reflecting a changing ADF leadership model
- A force preparing for a more contested region — with energy security, supply chains, and Indo-Pacific stability now central considerations
The appointments signal a Defence Force being reshaped not just structurally, but culturally — with leaders who have operated across tactical, operational and strategic levels now tasked with navigating one of the most complex security environments in decades.